The correct answer is A. Viviparous.
Viviparous animals give birth to live young. The young are nourished by the mother’s placenta while they are developing in the womb. Marsupials are a type of viviparous animal. The young marsupials are born at a very early stage of development and then crawl to the mother’s pouch, where they continue to develop and are nourished by the mother’s milk.
Oviparous animals lay eggs. The eggs are fertilized outside the body of the mother and then hatch after a period of incubation. Birds, reptiles, and amphibians are all oviparous animals.
Ovoviviparous animals lay eggs, but the eggs develop inside the mother’s body. The young are nourished by the yolk of the egg, but they also receive some nutrients from the mother’s blood. Sharks, snakes, and some lizards are ovoviviparous animals.
A distinct category is a category that is not included in any of the other categories. Marsupials are a distinct category of animals because they give birth to live young, but they do not do so in the same way as placental mammals.